The present invention relates to apparatus and methods for preparing shellfish for consumption and, more particularly, relates to apparatus and methods for eviscerating shellfish such as scallops.
In order to prepare shellfish for human consumption, it is necessary to remove the edible portion from the shell. With bivalves such as scallops, the edible portion comprises the adductor muscle which open and closes the shells. Various methods have been devised for separating the shells and dislodging the adductor muscle therefrom. Several such methods are disclosed in U.S. Pat. No. 3,528,124 to Wenstrom et al. These methods generally comprise shocking the shellfish by striking it against an immovable object, heating the shellfish for a time sufficient to separate the adductor muscle from the shells but not so long as to cook the muscle, and shocking the shellfish a second time against an object to separate the shells and the adductor muscle.
However, once the adductor muscle has been separated from the shells, further processing is required before it is suitable for consumption. The viscera of the shellfish surrounds the adductor muscle and generally must be removed before the muscle is cooked. One of the challenges faced in removing the viscera is to completely remove the viscera without removing any of the edible meat. Additionally, inasmuch as the scallops are relatively small, it is important to quickly and efficiently remove the viscera in order to make the process economical.
U.S. Pat. No. 3,257,684 to Wenstrom et al. discloses a method and apparatus for separating the adductor muscle of the scallop from the viscera. In the device disclosed in that patent, the adductor muscle with the viscera attached thereto is placed over an opening in a support, such opening being of a size about the same size as the muscle to be removed. The muscle is then forced through the opening to shear the viscera from the muscle. In one embodiment disclosed in the patent, the muscle is forced through the opening with a rod after the muscle is aligned with the opening by hand. In another, embodiment, a provision is made for holding the viscera about the opening while the aligned muscle is forced through the opening. Other embodiments include means for forcing the muscle through the opening by differential pressure, such as by a vacuum in one instance and by air pressure or hydraulic pressure in another instance.
U.S. Pat. No. 3,129,456 to Renfroe discloses an automatic process and apparatus for eviscerating scallops. In this process, a generally cylindrical viscera bearing scallop muscle is fed in an axial direction into the apparatus where the viscera is severed from the muscle. The severing is performed by a pair of cutting elements relatively movable in cooperative shearing relationship. In one embodiment, a knife is moved across the face of a perforated wall in conformity therewith to affect a shearing action between the knife and the edges of the perforations. The perforations are too small to permit passage of the muscles but the viscera moves freely through the perforations to be discharged. Suction can be applied to the opposite side of the perforated wall to facilitate severance and removal of the viscera. The muscles are rotated about their axes until all of the viscera is removed.
A further apparatus and method for eviscerating scallops is disclosed in U.S. Pat. No. 3,562,855 to Willis. In this process, scallop muscles and attached viscera are positioned on the upper surface of an inclined path formed by a plurality of rollers. Viscera is pulled from the scallop muscle and through the nip formed by adjacent rollers by rotating the upper portion of adjacent rollers toward each other. Detached viscera is cleaned from the rollers below the inclined path. The advance of the scallop muscles down the path is controlled by intermittently rotating the upper portion of adjacent rollers away from each other to permit the lower of the adjacent rollers to advance the muscle down the path and by spraying a flow of fluid such as water on at least some of the muscles on the path to affect their rate of movement down the path.
Still another method and apparatus for eviscerating scallops is disclosed in U.S. Pat. No. 3,665,554 to Wenstrom et al. In this process, the adductor muscles and attached viscera are delivered to an elongated stationary expanded metal plate. The metal plate is perforated and has an undulated irregular surface providing closely spaced projections. A plurality of spaced, flexible pusher plates cooperate with the perforated metal plate to remove the viscera from the adductor muscles as they are pushed along the plate. As a muscle and viscera are pushed along the plate, the viscera tends to fall through the openings in the plate and portions of the viscera are caught and pinched by the edge of the pusher plate against the projections of the metal plate.
The '554 patent discloses a second method and apparatus for eviscerating scallops in which a series of contiguous rollers are geared together so that adjacent rollers rotate in opposite directions. The rollers are rotated in one direction for about one and one-half seconds and then are reversed in direction for about one and one-half seconds. The rollers are formed from metal and have an embossed plastic covering of a nature such as to grip the viscera without damage to the scallop meat.
The '554 patent discloses a further method and apparatus for eviscerating scallops in which the contiguous rollers are arranged to be rotated in the same direction with or without reversal. The rollers can have either smooth or embossed surfaces. Alternating rollers are arranged to rotate at about twenty percent more speed than the other rollers. Accordingly, as the scallop meats are deposited between a pair of rollers, the faster rotating roller pulls the viscera against the frictional resistance of the slower moving roller to tear the viscera away from the scallop muscle and passes the viscera downwardly between the two rollers. The slower rotating roller can then advance the scallop meat down the bed of rollers where further viscera is removed.
While each of these processes provides a means for removing the viscera from the edible adductor muscle, they are still plagued with certain problems. For example, in the automatic processes which utilize a series of rollers, the bed of rollers generally has to be inclined to provide a driving force to move the scallops along the bed. However, it is still common for scallops to become stuck in a valley between a pair of rollers such that they do not progress down the eviscerating apparatus. Accordingly, what is needed in the art is a method and apparatus for eviscerating scallops which includes a means for propelling the scallops along the length of the apparatus. Such an apparatus and method are disclosed and claimed herein.